Morgan Meis in the Old Town Review:
In late April of 1975 the army of North Vietnam (NVA) completed its final defeat of the South Vietnamese army (ARVN) and headed toward Saigon. The mad dash to get out of Saigon created such indelible images as the scramble from the US embassy (actually a building nearby) onto the last few helicopters. When the NVA finally crashed through the gates of the Presidential Palace an historical era was over.
Interestingly, the communists decided to preserve parts of the Palace just as it was during the final days of Saigon, 1975. The place is, thus, something of a museum to a moment. Now, Saigon is Ho Chi Minh City, but the moment of victory, liberation, collapse, call it what you will, is eerily preserved in the basement of the Presidential Palace.
More here.